Wearable Shoe-Mounted Piezoelectric Energy Harvester for a Self-Powered Wireless Communication System

This study covers a self-powered wireless communication system that is powered using a piezoelectric energy harvester (PEH) in a shoe. The lead-zirconate-titanate (PZT) ceramic of the PEH was coated with UV resin, which (after curing under UV light) allowed it to withstand periodic pressure. The PEH was designed with a simple structure and placed under the sole of a shoe. The durability of the PEH was tested using a pushing tester and its applicability in shoes was examined. With periodic compression of 60 kg, the PEH produced 52 μW of energy at 280 kΩ. The energy generated by the PEH was used to power a wireless transmitter. A step-down converter with an under-voltage lockout function was used to gather enough energy to operate the wireless transmitter. The transmitter can be operated initially after walking 24 steps. After the transmitter has been activated, it can be operated again after 8 steps. Because a control center receives signals from the transmitter, it is possible to check the status of workers who work outside at night or mostly alone, to detect emergencies.